1. Field of the Invention
The present invention relates to an attachment structure of an adapter which can be engaged with and detached from an electronic device such as a camera, more particularly, improvement of an attachment structure of an adapter including therein a battery for supplying power to an electronic device such as a camera.
2. Description of the Related Art
A camera which is in general use includes a battery chamber in its main body. A specific battery or a dry battery or the like is set into the battery chamber, and power is supplied to circuits in the camera, thereby performing various functions.
The size of such a battery chamber is limited. As a result, the capacity of the battery is determined, and the number of photographs which can be taken is thus limited. Therefore, in order to take a large number of photographs, it is necessary to carry a number of batteries, and carry out battery-exchange during photographing.
In recent years, in order to satisfy the above requirement, a battery adapter has been developed which can be engaged with and detached from the camera body, and includes a battery pack having a large capacity in the battery adapter. Such a battery adapter is engaged with the camera body by utilizing a screw hole for tripod which is provided in, e.g., a bottom portion of the camera body.
Jpn. Pat. Appln. KOKAI Publication No. 57-58133 discloses a technique in which a camera body and an electric driving device to be engaged with a bottom portion of the camera body are positioned by their relatively positioning pin and tripod screw.
In the attachment structures of the camera body and the device to be engaged with the camera body, disclosed in Jpn. Pat. Appln. KOKAI Publication No. 57-58133, the camera body and the electric driving device to be engaged with the bottom portion of the camera body are positioned by their relatively positioning pin and tripod screw as described above. Due to this positioning, contacts of the camera and those of the electric driving device are electrically connected to each other.
In the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 57-58133, the camera body and the device to be engaged with the camera body are positioned in two positions only, i.e., the relatively positioning pin and tripod screw. Then, when positioning is effected, an electrical connection between the contacts of the camera and those of the electric driving device is achieved.